The present invention relates to a polarized-light scatterometer, and in particular to a polarized-light scatterometer that is capable of measuring the thickness of a film coated on the partial of a substrate.
There are a lot of methods for measuring the thickness of a film, such as using an ellipsometer or a transmission spectrum. However, both of them are poor at measuring the thickness of non-transparent film. If the thickness of a film is measured by the eddy-current method or the electrical resistance method, then a substrate material that is not-conducting and not-magnetic must be employed.
In addition, when the stylus method is used to measure the thickness of a film coated on the partial of a substrate, the film may be scraped by the stylus during the measurement, affecting the precision of the measurement.